1. Field of the Invention
This invention relates to the technique for manufacturing semiconductor devices, and more particularly to a mechanism for and a method of peeling adhesive tape bonded to segmented semiconductor wafers, an apparatus for and a method of peeling adhesive tape bonded to segmented semiconductor wafers, a pickup apparatus and a pickup method which include a mechanism for peeling adhesive tape bonded to segmented semiconductor wafers and pick up each semiconductor chip, a semiconductor device manufacturing apparatus and a semiconductor device manufacturing method which include the peeling mechanism, the peeling device, or the pickup apparatus.
2. Description of the Related Art
Generally, in the processes of manufacturing semiconductor devices, a semiconductor wafer on which elements have been formed is divided into segments along dicing lines or chip division lines, thereby forming a plurality of semiconductor chips. FIGS. 1A and 1B show a state of a segmented semiconductor wafer (or semiconductor chip) 100, which is bonded to adhesive tape 101a. FIG. 1A is a perspective view of the wafer 100. FIG. 1B is a sectional view of the wafer 100 taken along line 1B-1B of FIG. 1A. Each semiconductor chip 100 is picked up from the adhesive tape 101a and undergoes the mounting processes, including the process of mounting the chip on a leadframe or TAB tape and the process of sealing the chip into a package, which completes a semiconductor device.
When each semiconductor chip 100 is picked up, the reverse of the semiconductor wafer adhering side of the adhesive tape 101a is bonded to another adhesive tape 101b adhered to a wafer ring. Then, the adhesive tape 101a is peeled and the wafer ring is installed on a pickup apparatus, which picks up each semiconductor chip 100.
FIG. 2 is an enlarged sectional view of the main part of the mechanism for picking up semiconductor chips 100 from the adhesive tape 101b in a conventional pickup apparatus. When semiconductor chips 100 are peeled from the adhesive tape 101b bonded to the wafer ring and picked up, thrust pins (or pick-up needles) 102 are pushed up (or raised) via the adhesive tape 101b from the backside of the semiconductor chip 100, thereby peeling the semiconductor chip 100 with the help of the elastic force of the adhesive tape 101b. The base of each thrust pin 102 is provided on a pin holder 103 in such a manner that it is located in a position corresponding to each corner or the central part of the semiconductor chip 100.
The procedure for peeling the semiconductor chips 100 from the adhesive tape 101b is as follows. First, a holding table on which the adhesive tape 101b to which the semiconductor chips 100 are bonded is fixed is moved in such a manner that a semiconductor chip 100 to be picked up is positioned above the thrust pins 102. Next, the position of the semiconductor to be peeled is sensed and a mark for determining whether the chip is good or bad is sensed. Then, a vacuum is drawn from the inside of a backup holder 104, thereby causing the adhesive tape 101b to adhere to the top surface of the backup holder 104 by suction and be fixed. In this state, the pin holder 103 on which the thrust pins 102 are provided is raised, thereby causing the thrust pins 102 to stick out of the top surface of the backup holder 104, with the result that the thrust pins push up the semiconductor chip 100 from the backside via the adhesive tape 101b. 
In recent years, to incorporate semiconductor chips into, for example, a card-like thin package, there have been strong demands toward making semiconductor chips thinner. The backside of a semiconductor wafer is polished, grounded, and etched to a thickness of 100 μm or less. However, when a semiconductor chip is made as thin as 100 μm or less, the chip cracks, or cracks occur, at the time of bonding the chip to another adhesive tape, which decreases the manufacturing yield. That is, after the semiconductor chips 100 bonded to the adhesive tape 101a are bonded to another adhesive tape 101b bonded to the wafer ring, cracks take place in the semiconductor chips at the time of peeling the adhesive tape 101a. When the semiconductor chips are bonded to another adhesive tape, there arises another problem: the semiconductor chips 100 touch each other, permitting them to chip, which degrades the quality of the semiconductor devices.
When each semiconductor chip is picked up, cracks or chipping also occurs. The crack problem arising at the time of picking up each semiconductor chip with a thickness of 100 μm or less will be explained in further detail by reference to FIGS. 3A, 3B, 4A and 4B. In the case where a semiconductor chip is very thin as described above, even when the periphery of the semiconductor chip 100 (particularly its corners) has come off, the semiconductor chip 100 warps concavely before peeling as shown in FIG. 3A because the speed at which the adhesive tape 101b peels is slower than the speed at which the thrust pins 102 go up, with the result that cracks take place as shown in FIG. 3B. Alternatively, as shown in FIGS. 4A and 4B, when the backside of a semiconductor chip 100 is pushed up by the thrust pins 102, with the adhesive tape 101b intervening between them, cracks occur in the part where the semiconductor chip 100 and the thrust pins 102 are in contact with each other in a state where only the corners are peeled, or the thrust pins 102 penetrate, with the result that the chip cracks. When the thickness of the semiconductor chip is 100 μm or more, such a phenomenon is less liable to take place because the strength (in the direction of thickness) of the semiconductor chip is great on account of the adhesion of the adhesive tape 101b to the semiconductor chip 100.
As described above, when a semiconductor chip is made thinner, the resistance of the semiconductor chip to breaking decreases, with the result that a decrease in the quality due to cracks or chipping and a drop in the yield cannot be avoided by a conventional mechanism for and method of peeling adhesive tape and by a conventional apparatus for and method of picking up semiconductor chips. Therefore, there have been demands for improvements in not only that mechanism, apparatus, and method but also an apparatus for and a method of manufacturing semiconductor devices which include the mechanism, apparatus, and method.